Combustion chamber swirler



Sept. 6, 1960 G. R. BENSON COMBUSTION CHAMBER SWIRLER Filed March 31, 1959 INVEN TOR aioRcs R. BENSON A7 TORNEY CONIBUSTION CHAlVlBER SWIRLER George R. Benson, East-Hartford, Conn., assignor to United Aircraft Corporation, East Hartford, Conn., a corporation of Delaware Filed Mar. 31, 1959, Ser. No. 803,175

8 Claims. c1. 60-3965) 'This invention relates to a burner can or flame tube for the combustion system of a gas turbine engine.

One form of combustion system for this purpose is disclosed in Brown Patent No. 2,676,460 in which the burner can has an inner sleeve defining a central air passage such that combustion takes places in the annulus defined between the outer sleeve of the burner can and the inner sleeve. A feature of the present invention is a swirler in the inner sleeve to impart a swirl to the air discharging into the burner space from the central passage.

In the burner can of the Brown patent above identified, thev downstream end of the central air passage is closed so that any air entering this passage is discharged through the small openings in the side walls of the passage. One feature of the present invention is the re placement of this closed end on the passage with a swirler so that additional air from the passage may enter the combustion space with a swirling action.

Other features and advantages will be apparent from the specification and claims, and from the accompanying drawings which illustrate an embodiment of the invention.

Fig. l is a sectional view through a burner can.

Fig. 2 is an end view of the center tube.

The burner can in the drawing has an outer sleeve 2 and an inner concentric sleeve 4. These sleeves are interconnected at the upstream ends by an end cap 6 on the burner can which is in the form of a ring extending between the inner and outer sleeves. The upstream end of the inner'sleeve 4 is unobstructed, as shown. A row of fuel nozzles 8 are positioned in openings 10 in the end cap 6 and fuel from these nozzles is discharged into the annular space 12 defined between the two sleeves. In this space combustion of the mixture of fuel and air takes place.

The burner can is positioned in a duct as is well known and shown, for example, in the Brown P-atent No. 2,676,460 so that air under pressure is flowing in a generally axial direction around the burner can and also into the central passage 14 within the sleeve 4. The products of combustion are discharged from the burner can into a transition piece 16 connected to the downstream end of the outer sleeve 2. This transition piece is cylindrical at its upper end 18 to receive the end of the sleeve 4 and becomes segmental in shape at its downstream end 20. 1

For the admission of air to the combustion space 12 the inner and outer sleeves are made up of short tapering rings overlapping one another and having rows of air inlet openings 22 therein. This form of overlapping rings is described in a Highberg Patent No. 2,801,520.

In accordance with the present invention the downstream end of the inner sleeve 4 has positioned therein United States Patent 0 2,951,339 Patented Sept. 6, 1960 ice a row of swirl vanes 24. These vanes are carried by an outer ring 26 secured to the sleeve 4 and extend radially inward. Each vane is positioned at an acute angle to a longitudinal plane with the result that the air passing in a generally axial direction over the vanes is caused to swirl in a helical manner while continuing its generally axial flow and the inner ends of the swirl vanes 24 are connected to and support a dome-shaped center piece 28. The tip of the dome faces in a downstream direction to provide a faired surface for defining an inner wall for the air flowing helically through the swirl vanes 24. This imperforate dome limits the flow through the end of the sleeve 4 so that all of the air entering the combustion space through the end of the sleeve will be restricted to a flow over the swirl vanes and thus enters the space in a helical path. It will be noted that the sleeve 4 in the arrangement shown terminates at a point forward of the downstream end of the outer sleeve 2.

With the air admitted into the combustion space through the end of the sleeve 4 the air is effectively and more uniformly mixed with the products of combustion. Thus the hot gas discharging through the segmental end 20 to the turbine nozzle will be at a more nearly uniform temperature over the entire area.

It is to be understood that the invention is not limited to the specific embodiment herein illustrated and described, but may be used in other ways without departure from its spirit as defined by the following claims.

I claim:

1. In a burner can for the combustion system of a gas turbine, a sleeve forming the outer wall of the can, a closure for the upstream end of the sleeve, a plurality of fuel nozzles arranged in a ring in said closure concentrically of said sleeve, said closure having a central opening within the ring of nozzles for the admission of air axially therethrough and swirl means extending transversely across said central opening for imparting a helical swirl to the air entering the sleeve from said central opening.

2. A burner can as in claim 1 in which the central opening has an inner sleeve attached thereto and pro jecting downstream therefrom within the first sleeve with the swirl imparting means positioned transversely across said inner sleeve.

3. A burner can as in claim 1 in which an inner sleeve concentric to the first sleeve extends in a downstream direction from said central opening and is supported by said closure with the swirl imparting means located at the downstream end of said inner sleeve.

4. A burner can as in claim 1 in which an inner sleeve is positioned within and concentric to the first sleeve and is attached to and extends downstream from said central opening with the inner sleeve terminating at a point upstream of the downstream end of the first sleeve.

5. In a burner can, concentric inner and outer sleeves defining an annular space therebetween and an upstream closure extending between said sleeves and closing the upstream end of the space between said sleeves, the inner sleeve terminating at a point upstream of said outer sleeve, in combination with a swirler positioned transversely across the downstream end of the inner sleeve for imparting a helical swirl to the air passing in an axial direction into the burner can from said inner sleeve.

6. A burner can as in claim 5 in which the swirler includes a ring of swirl vanes and a central imperforate portion.

7. A burner can as in claim 5 in which the swirler includes a ring of swirl vanes and a central imperforate portion with the peak of the dome directed downstream to define a curved surface over which swirling air past the vanes is directed.

8. A burner can as in claim 5 in which the closure supports a ring of fuel nozzles, the inner and outer sleeves having rows of inlet openings in the walls thereof and in which the inner wall terminates forward or the down stream end of the outer sleeve.

References Cited in the file of this patent UNITED STATES PATENTS 2,175,866 Arnold Oct. 10, 1939 5 2,813,397 Fisher et a1. Nov. 19, 1957 FOREIGN PATENTS 800,512 Great Britain Aug. 27, 1958 

